Wilhelm schmidt



W. SCHMIDT.

Patented VMay 28, 1895.

(No Model.)

COMBINED TUBULAR BOILER AND SUPERHEATER.

No. 5:,s9,827.A

" UNITED STATES PATENT EE'ICE.

VILHELM SCHMIDT, QF WILHLMSHHE, GERMANY.

COMBINED TUBULAR BOILER AND SUPERHEATER.

SPECIFICATION forming part of Letters Patent No. 539,827, dated May 28,1895. Application filed December 22, 1893l Serial No.494,485 (No model.)

To a/ZZ whom, it may concern:

Be it known that I, WILHELM SCHMIDT, a subject of the King of-Prussia,German Emperor, and a resident of Wilhelmshhe, near Cassel, in theProvince of Hesse-Nassau, Kingdorn of Prussia, German Empire, haveinvented a new and useful Combination Consisting i of a Tubular Boilerand a Superheater, of

which the following is an exact specification.

This invention refers to combinations of steam-boilers and superheaters,and my improvements in such combinations relate, rst, to the arrangementof a tubular boilerwith coiled pipes, and, second, to the arrangement ofa reservoir connected with both ends of the boilercoil,but with only oneend of the superheater-coil, as willbe more fully describedKhereinafter.

Before entering into thedetails of the mode of construction of myimproved combination shown inthe drawing, I think it necessary7 to givesome preliminary statements and explanations, in order to render theidea of the invention perfectly clear and intelligible.

If steam is to be superheated to a temperature of about 300, theheating-gases should have, as is well known, a temperature of at leastfrom 500o to 600. The said former temperature will be reached best byarranging the superheater above the steam-generator, and exposing ittothe furnace-gases of the same,`or, in other words, by arranging the,

superheater behind the steam-generator with regard to the direction ofthe furnace-gases of the latter, and exposing it to a zone of saidgases, in which the temperature amounts to about 600. The regases need,thus, be cooled down by the boiler proper but to about 600, whilegenerally,in a steamgenerator without superheater an exhaust of the heatdown to 250 is required. As is well known, however, the greatest part ofsteam is generated in the fore-part of a boiler, the remaining part,that is generated by exhausting the heat from 600 down to 250, being ofbut small quantity, and necessitating comparatively largeheating-surfaces. Extended trials made with locom0tive-engines haveproved, that about fifty per cent. of the whole of the steam isgenerated in the small part surrounding the re-box. It results fromthis,

that, when arranging a superheater for temperatures of about 300 aboveor behind a steam-generator, the latter not only may have acomparatively small heating-surface, but should have such a one; and itwill be seen, further, that such boiler with superheater will yield atleast the same effect, as a larger boiler, that v.consumes a likequantity of fuel, since thefurnace gases of both boilers are exhaustedin like degree, t'. e., are escaping into the smoke-stack with -the likelow'vv temperature. Owing to these facts, now, the boiler or generatoremployed in 'my improved combination is composed of coils oreoiledpipes. These latter offer, in themselves,certain advantages for everyboiler-plant. They could, however, not be, employed in a more extensivedegree, especially for large plants, as there arise in the practical useof them serious drawbacks difficult to be overcome, as'will be shown inthe following.V

The main point to be considered in the use of coiled pipes assteam-generators consists in the rapid circulation of the water or ofthe mixture of water and steam within the coils. Such circulation isindispensably requisite. The same is considerably hindered or delayed,however, by the great friction arising between the Water and the innerwalls of the pipes, especiallyT if the latter are of a somewhat greatlength and of but small inner section. This disadvantage could beovercome, seemingly, by using pipes with larger section. This section,however, necessitates dimensions of such size, that it is nearlyimpossible to bend such pipes. A perfect change, however, in all thesecircumstances occurs, if the tubular boiler withcoiled pipes is combinedwith a superheater. There is no necessity any more for providing s0large a heating surface for properly exhausting the heat of the tireorfurnacegases, but a boilerof but'vthe fifth or sixth size with coils ofbut smallsection will be sufficient for delivering the desired effect,even if a larger number of horse-powers is required.

The heat of the tire need not be cooled by the heating-surfaces of theboiler proper downto 250, as this is performed by the superheater; andthe generation of steam will be a regular one, and free of shocks, asthe circulation of the Water, or of the mixture of water and steam.

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respectively, within the short coil with its small section is a veryactive one. The best elfect, however, of the combination of a tubularboiler (with coiled pipes) with a superheater is attained by arranging areservoir between the boiler-coil and the superheating coil, for thepurpose of separating water and steam. I have represented thisarrangement in the accompanying drawings, in which is shown a verticalsection through the tubulous boiler, the superheater and the saidreservoir.

The coil d of the tubulous boiler, which is heated from the furnace b,is connected by its two ends a a2 with the reservoir c, coil-end aterminating into the lower compartment of the reservoir by the mediationofva bent tube a5 extending upward within said compartment; coil-end a2terminating into the upper compartment of the reservoir by the mediationof a bent tube a3 likewise extending upward within that respectivecompartment. The further details ot' the reservoir will be more fullydescribed hereinafter.

The uppermost portion of the reservoir forms a steam-dome, and thesaturated steam is led from that dome by the mediation of pipe d intothe superheating-coil cl, from which the superheated steam is led awayby pipe d'2. The feed-water for the boiler, or for coil a respectively,enters the latter through the pipes a5 a', and leaves the coil, afterbeing heated and partly turned into steam within the same, bythe pipesa2 a3. The mixture of water and steam separates within the uppercompartment of the reservoir c, the steam collectingr within thedome,.the boiling water mixing with the feed-water, and heating thesame.

The superheater consists of a number of superposed flat horizontalcoils, which are connected with each other to a continuous passage. Thisconnection of the coils, however, is made in such a way, that twodivisions are formed out of them; the first division, next to theboiler-coil, being passed by the steam in a direction like that of thefurnace-gases; the other division being passed 4by the steam in theopposite direction; that is to say, opposite to the direction of thefurnace-gases. Both divisions are connected by the bent tube d3. Thesaid superheating-coils are arranged in the annular space between theouter wall e and the inner wall e. The furnacegases coming from there-place b are led through the said space, and leave the whole apparatusat f. It will be seen now, that the circulation of the water,`or of themixture of water and steam respectively, within the boiler-coil will bea very intense one, as, first the said coil is but short, and has but asmall section; and as, second, the contents of coil a are constantlyunder the pressure of the water-column within the lower compartment ofreservoir c. The generation of steam is, therefore, a very intense andrapid one, as well as free of shocks, and the steam then enters thesuperheatin g coils without the least addition of water, as the latteris perfectly kept back by the reservoir. The water now circulates againand again through the boilercoil, so that the whole of the water withinreservoir c is heated to a high degree of temperature. This circulationwill, as a matter of course, be the more active the greater thedifference in pressure between the water-column within the lowercompartment of the reservoir, and the waterand steamcolumn within theboiler-coil; and further, the less the resistance offered by thefriction between the said waterand lsteam-column and the inner walls ofthe boiler-coil. It results herefrom, that the whole of the watercontained within, or entering, the said boilercoil cannot be turned intosteam at so rapid a circulation, and it becomes thus, necessary toprovide the reservoir c for separating both parts of the water-and-steammixture leaving the boiler-coil, as but the `steam can be permitted toenter the superheating-coil, while the hot water must remain.

Concerning now the special construction of the reservoir, the latter isdivided into two superposed compartments by a horizontal plate c havingsecured to it aver-tical tube g extending downward to the neighborhoodot the bottom c2. The vertical tube a5 communieating with end a of theboiler-coil is arranged in the same compartment of the reservoir, andextends upward to the neighborhood of plate c aforementioned. Thepurpose of this arrangement is to separate and precipitate sediments andthe like contained in the feed-water, for preventing the boiler-coilfrom becoming incrustated. The feed-water enters the upper part of thereservoir through the funnel h, and the sediments separated by theheating of the water ow, together with the latter, down into the undercompartment of the reservoir through tube g. The water, then, in orderto enter the opening of tube a5, flows upward again, while the sedimentsremain back, and precipitate on the bottom c2.

The uppermost part of the vertical boilercoil a, or that part situatedbetween the coil a proper. and the pipe 0,2, is formed to a horizontalcoil a4, the purpose of which is to break the intense heat discharged bythe fire, so that the superheater is prevented thereby from becomingpervious.

Having thus fully described the nature of this invention, what I desireto secure byLetters Patent of the United States is 1. The combinationwith a superheater, consisting of a column of horizontal coils formingtwo superposed divisions, of a tubular boiler also consisting of coiledpipes, the ends of the boiler coil being connected with a reservoirdivided in two compartments, one of the latter being adapted to causethe vseparation of the sediments, the other the precipitation of thesame, said former compartment being connected with the lower end of thelower superheating coil-column, the

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upper end of the latter being connected with the upper end of the uppersuperheating coilcolumn,rfor the purpose as described.

. 2. The combination with a superheater, consisting of a column ofhorizontal coils forming two superposed divisions, of a tubular boileralso consisting of coiled pipes, the ends of the boiler coil beingconnected with `a reservoir divided in two compartments by a plateallowing communication between the said compartments. one of the latterbe-` ifng adapted to .cause the separation of the sediments, the otherthe precipitation of the same, said former compartment being connectedwith the lower end of the lower super- 'heating coil-column, the upperend of the latter being connected with the upper end of the uppersuperheating coil column, for the purpose as described.

3. The combination with a superheater consisting of a column ofhorizontal coils forming two superposed divisions, of a tubular boileralso consisting of coiled pipes, the ends of the boiler coil beingconnected with a reservoir divided in two superposed compartments by aplate carrying'a tube, the

l to cause the separation of the sediments, the` upper of saidcompartments being adapted lower the precipitation of the same, saidtube being adapted to convey the sediments from the upper to the lowercompartment, said upper compartment being connected with the lower endof the lower superheating coil-column, the upper end of the latter beingconnected with the upper end of the upper superheating coil-column, forthe purpose as described.

4. The combination with a Snperheater consisting of acolumn ofhorizontal coils forming two superposed divisions, of a tubular boileralso consisting of coiled pipes, the ends'of the boiler-coil beingconnected with a reservoir divided in two superposed compartments by aplate carrying a tube, the upper of saidcompartments being connectedwith the upper end of the boiler-coil, and with the feedpipe, and beingadapted to cause the separation of the sediments, the lower compartmentbeing connected with the lower end of the boiler-coil, this endterminating shortly below the bottom-plate of the upper WILHELM SCHMIDT.

Witnesses:

R. HERPICH, E. Soiunrzn.

